In medical technology and medicine, a plurality of treatments of a human or animal body are known which imply the use of one or more compression devices for exerting pressure onto a body or a body part such as a limb of the human or animal user. Without restricting the present invention to a specific use, the treatment of venous diseases may be named, such as chronic venous insufficiency (CVI). In CVI, generally, veins are incapable of pumping a sufficient amount of oxygen-depleted blood to the heart. This disease, mostly, is closely related to thrombosis and, in many cases, implies an insufficient function of venous valves. Venous insufficiency generally may occur in a plurality of body parts such as limbs. Most frequently, legs or parts of the leg may be affected by venous insufficiency, such as calves.
As known in the art, venous insufficiencies and/or other types of diseases may be treated by compression therapy. Therein, a pressure is exerted onto the body part affected by the respective disease. As an example, compression bandages may be used, such as single layer or multi-layer compression bandages. A plurality of bandages is commercially available, mostly flexible bandages having a specific stiffness.
When using compression therapy, a number of precautions have to be taken in order to avoid injuries by overexerting pressure to the body part on the one hand side and exerting insufficient pressure on the other hand. Therefore, a plurality of devices is known in the art for monitoring pressure exerted onto the body part during compression therapy.
In WO 2008/003920 A1, a patient compliance monitor for monitoring compliance of a patient to a treatment regime for treatment of a medical condition is disclosed. The compliance monitor comprises measurement means for measuring an external physical parameter acting on a limb of said patient, the external physical parameter having influence on the medical condition experienced by said limb. Inter alia, the use of a tilt sensor for measuring the tilt of a limb of said body, the use of a movement sensor for monitoring motion of said limb, the use of a pressure sensor for measuring the pressure applied to a region of said body, and the use of a thermometer for monitoring the ambient pressure around said body are disclosed. Further, recording means for recording data as well as comparative means for comparing the recorded data with data indicative of the treatment regime are disclosed, in order to determine patient compliance to the treatment regime.
US 2010/0010405 A1 discloses an apparatus and method for cyclically compressing the limb of a patient to improve blood flow in the limb. Inter alia, the use of a sensing device is disclosed which is capable of sensing a characteristic of a compression therapy performed by using the compression device.
In US 2011/0015498 A1, a system and a garment are disclosed which incorporate sensors that can be used for measuring or monitoring pressure or forces in feet, the stumps of limbs of an amputee that are fitted with prosthetic devices or any other parts of the body that are subject to forces when external pressure inducing devices are employed. Therein, one or more pressure sensors are integrally incorporated into a flexible substrate, fixed to the substrate or removably connected to the substrate.
Further, various monitoring systems are known which make use of a measurement of one or more key figures indicating patient compliance with compression therapy. As an example, US 2012/0083712 A1 discloses a monitoring system which is capable of monitoring venous refill time (VRT) via a pressure sensor in a bladder of a compression system. A controller of the compression system correlates the monitored VRT to a predetermined threshold to determine whether the patient is using the compression system.
In U.S. Pat. No. 6,231,532 B1, a method for augmenting blood circulation in the limb of a patient is provided. Again, the venous refill time of the patient is measured. The limb is wrapped with a compression sleeve having at least one pressurizable chamber. The chamber is pressurized for a predetermined period of time to compress the limb and cause blood to flow out of the limb. The chamber is depressurized until the pressure in the chamber reaches a lower value, and the chamber is closed. The pressure in the chamber is sensed and the venous refill time is determined by sensing when the pressure reaches or will reach a plateau.
In U.S. Pat. No. 7,127,370 B2, an attitude indicator device for detecting, indicating and/or logging the positional attitude of an individual in response to deviation from a set of one or more reference angles is disclosed. The device is mounted to the thigh of a patient and measurements are taken from an acceleration sensor within the device. The acceleration measurements are communicated to a receiver when the measurements deviate from acceptable thresholds, whereby the receiver indicates an alert condition.
Further, methods and devices are known which generally monitor the efficacy of compression therapy. Thus, in H. Partsch et al.: Measurement of lower leg compression in vivo: Recommendations for the performance of measurements of interface pressure and stiffness: A consensus statement, Dermatol Surg. 2006; 32: 224-233, general recommendations are provided for measuring the efficacy of compression systems by using one or more pressure sensors. Similarly, in G. Mosti et al: Comparison between a new, two-component compression system with zinc paste bandages for leg ulcer healing: a prospective, multi-center, randomized, controlled trial monitoring sub-bandage pressures, Wounds 2011; 23(5): 126-134, systems and methods for monitoring pressure exerted by compression systems are disclosed. Both documents provide an overview of different measurement techniques which may be used for determining exact pressures in compression therapy. Further, measurement routines implying resting and working pressure measurement on both legs are disclosed.